Fuel filler tube assembly and manufacturing method

ABSTRACT

A method of forming a filler tube includes forming a funnel insert, forming a funnel portion in a first end of a filler tube, and joining the funnel insert and the funnel portion of the filler tube. The funnel portion includes a transition portion configured to induce a swirl to passing fuel for venting vapors from the gas tank during fuel filling. A fuel filler tube assembly includes the funnel portion including a tubular body defining a larger inlet and a smaller outlet, the position of the inlet relative the outlet and an internal configuration of the tubular body therebetween inducing a swirl to inventing vapors from fuel flowing through the tubular body. The larger inlet receives a funnel insert including a nozzle opening positioned to cooperate with the internal configuration of the tubular body.

FIELD OF THE INVENTION

The present invention relates to a fuel tank system for an automobileand, in particular, to an improved filler tube assembly.

BACKGROUND OF THE INVENTION

Reducing gasoline vapor loss in fuel tank systems is becomingincreasingly important in the automobile industry. A solution to thisproblem has been to reduce the diameter of an outlet end of a fuel tankfiller neck relative an inlet end. While this approach has achieved somesuccess, the success has been limited because as the diameter of thefiller neck is decreased, the resistance to gasoline flow is increased.This increased resistance has caused other problems, notably pressurebuild up in the filler neck, often causing the fuel nozzle to shut offbefore the fuel tank is full.

Permeability of materials from which the filler tube assembly ismanufactured also presents another design issue because the fuel vaporsmay diffuse through the fuel tank system components; various types ofmild steels, for example, permit fuel vapor diffusion. Such fuel vapordiffusion further increases as steel components corrode over time.

A manufacturing issue with current filler neck designs is the method bywhich the diameter of inlet and of the filler neck is increased relativethe diameter of the outlet end in order to provide a sufficient diameterto accept a gas nozzle during refueling. While filler necks are oftenmade by a process of repeated reductions and expansions of a seamed,welded tube, this mechanical process structurally weakens the tube,resulting in an increasing tendency for the tube to leak at the seam.

To address this issue, manufacturers have begun using a seamless tube,which addresses the seam-leak problem but requires mechanically joiningthe outlet end of the filler neck to a separate filler tube and couplinga nozzle retainer. Such prior art attempts will include U.S. patentapplication Ser. No. 09/454,103, now U.S. Pat. No. 6,330,893; U.S.patent application Ser. No. 09/998,113, now U.S. Pat. No. 6,588,459; andU.S. patent application Ser. No. 10/615,485, filed Jul. 8, 2003; each ofwhich is incorporated herein by reference. While these designs areimprovements, such a three-piece fuel filler tube assembly is relativelyexpensive to manufacture and assemble and necessarily requiresmechanical joints between the filler neck and filler tube, as well asbetween the nozzle retainer and the filler neck. Any joint in a fuelfiller tube assembly creates the possibility for vapor loss or fuelleaks through a defect or corrosion.

Moreover, with the necessity to assemble the parts post-manufacturing ofthe individual parts, variability in part dimensions—for example, thejoints between the filler neck outlet and the filler tube and betweenthe nozzle retainer and filler neck—as well as the quality of anysealing surfaces, can lead to an inferior product. Similarly,inconsistency in the orientation of features of the filler tubeassembly, for example, thread orientation relative a fuel cap sealingsurface or nozzle retainer orientation relative filler tube features,can lead to defective fuel filler tube assemblies through mistakes inthe assembly process.

SUMMARY OF THE INVENTION

A method of forming a filler tube assembly includes forming a funnelinsert, forming a funnel portion at a first end of a filler tube, andjoining the funnel insert in the funnel portion of the filler tube. Thefunnel portion is configured to include a transition portion forinducing a swirl to passing fuel, whereby vapors may be vented from thegas tank during fuel filling. The configuration includes forming aninlet at one end of the funnel portion and forming an outlet at theopposite end of the funnel portion. An axis of the inlet is offset fromthe axis of the outlet.

The method may further include forming a sealing surface above the inletopening to the funnel insert, perhaps by rolling over an edge definingthe inlet opening. The funnel insert may further include threads formedintegrally therein, the threads adapted to engage a fuel cap for sealingthe fuel tank system from the environment.

The filler tube is preferably formed by cutting a length of tube stockto form the filler tube. The funnel insert preferably includes anintegrally formed nozzle receptor.

An end of the filler tube opposite the funnel insert may be joined to afuel tank. Further, opposite ends of a vent tube may be joined to thefunnel portion of the filler tube and the fuel tank, respectively, inorder to provide ventilation for the fuel tank system.

A fuel filler tube assembly according to the invention includes a funnelportion of a filler tube including a tubular body defined in a largerinlet and a smaller outlet, the position of the inlet relative theoutlet and an internal configuration of the tubular body between theinlet and the outlet inducing a swirl to inventing vapors from fuelflowing through the tubular body. The larger inlet receives a funnelinsert including a nozzle opening position to cooperate with theinternal configuration of the tubular body. The internal configurationof the tubular body includes a tapered section of the tubular bodyhaving an elliptically shaped junction between a first portion of thetubular body including the inlet end and a second portion of the tubularbody including the outlet. The elliptically shaped junction lies on aplane inclined to be angled to an axis of at least one of the inlet andthe outlet. The filler tube and the funnel insert are preferably formedfrom a seamless tube.

The filler tube assembly may include a sealing surface formed integrallyabout an inlet opening of the funnel insert. The funnel insert mayfurther include integrally formed threads for receiving the fuel cap.

The filler tube assembly may include a vent tube connected to the fillertube. Further, the vent tube may be connected to a fuel tank that isalso connected to the filler tube.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a schematic view of a fuel tank system according to theinvention;

FIG. 2 is an exploded perspective view of the filler tube assemblyaccording to the invention;

FIG. 3 is a partial side view of a filler tube assembly according to theinvention;

FIG. 4 is a sectioned side view of the filler tube assembly according tothe invention;

FIG. 5 is a schematic illustration of the filler tube assembly accordingto the invention;

FIG. 6 is a schematic illustration of a method of forming threads in thefiller tube assembly; and

FIG. 7 is a schematic illustration of another method of forming threadsin the filler tube assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

With reference to FIGS. 1 and 2, a fuel tank system 10 generallyincludes a filler tube assembly 12, a fuel tank 14, and a fuel cap 16.The fuel tank system 10, which is supported by an automobile body 22,may further include a ventilation system 18, which is illustratedgenerally as a vent tube 20 extending between the filler tube assembly12 and the fuel tank 14.

The filler tube assembly 12 generally includes a funnel insert 30 and afiller tube 32 joined together at a joint 34, which may be brazed,welded, adhered or otherwise mechanically or chemically joined. Thetwo-piece assembly of the funnel insert 30 and the filler tube 32provides a fueling path from a fuel supply source, such as a fuel nozzle24, located exterior the automobile body 22 to the fuel tank 14 withinthe automobile body 22.

The filler tube 32 is a one-piece seamless tube extending between thefuel tank 14 and the funnel insert 30 in order to communicate fuel flowfrom the funnel insert 30 to the fuel tank 14. The filler tube 32, at afirst end 36, is coupled to the fuel tank 14. At a second end 38, thefiller tube 32 includes a funnel portion 40, which is a flared portionof the filler tube 32 including the second end 38 and a transitionportion 26. The transition portion 26 provides a tapered configurationdesigned to cause fuel flowing therethrough to swirl. The funnel portion40 of the second end 38 includes an axis offset axially from the axis ofthe first end 36 due to a generally elliptically shaped cross-section ofthe transition portion 26.

As shown in FIGS. 1 and 2, the funnel insert 30 is a one-piece seamlesstube having a first diameter portion 42 at an inlet end 44, a seconddiameter portion 46 at an insert end 48, and an integrally formed nozzleretainer 60. The first diameter portion 42 is larger than the seconddiameter portion 46 and is designed to receive the fuel cap 16, whichincludes a sealing ring 17 and a stem 15 including threads 13, and aconical portion 25 which joins the first and second diameter portions42, 46.

The first diameter portion 42 of the funnel insert 30 includes a sealingsurface 50 and threads 52, both of which are integrally formed whenmanufacturing the funnel insert 30. The sealing surface 50 will be agenerally planar radial extension formed about a circumference of aninlet opening 54 formed in the inlet end 44 of the funnel insert 30.With reference to FIG. 3, the sealing surface 50 provided about theinlet end 44 of the first diameter portion 42 of the funnel insert 30provides a sealing surface against which the fuel cap 16 seals whenthreaded into threads 52. The sealing ring 17 may be positioned betweenthe fuel cap 16 and the sealing surface 50.

The threads 52, which include thread segment 52 a and thread segment 52b, are formed in a sidewall 56 of the first diameter portion 42. Thethreads 52 are inner diameter threads extending radially into the firstdiameter portion 42 and mate with the threads 15 formed radiallyinwardly in the stem 13. Further, the threads 52 further function tohook or retain the fuel nozzle 24 during fueling through engagement withrings 80 of the fuel nozzle 24, as shown in FIG. 4. Note that thethreads 52 may be screw, quarter-turn, eighth-turn, or quick-turn threadconfigurations, as well as other known thread configurations.

The nozzle retainer 60 is formed at the insert end 48 of the seconddiameter portion 46 and includes a nozzle opening 62 and vent holes 64.Further, the nozzle opening 62 also axially offset in a radial directionopposite the transition portion 26 of the filler tube 32 in order todirect fuel supplied by the fuel nozzle 24, which when inserted isdisposed toward the transition portion 26, whereby a swirl motion may beinduced to the flowing fuel. The nozzle opening 62 further includes acylindrical wall 63 surrounding the nozzle opening 62 and extending inthe insert direction. The nozzle retainer 60 is positioned relative thethreads 52 in order that the nozzle opening 62 is axially offset in aradial direction laterally aligned with one of the thread portions 52 a,52 b. As shown on FIG. 4, the threads 52 and nozzle opening 62, throughtheir relative positions and generally offset orientation relative thefiller tube assembly 12, retain the fuel nozzle 24 in a properfuel-filling orientation.

The funnel insert 30 and filler tube 32 are assembled and joined at thejoint 34, such as by a braze, weld, adhesive or other mechanical orchemical joint. The assembled filler tube assembly 12, with the insertend 48 of the second diameter portion 46 inserted into the funnelportion 40 of the filler tube 32 creates a funnel member 70 havingintegrally formed therein the sealing surface 50, the threads 52, andthe nozzle retainer 60, as shown in FIG. 5. Overall, the configurationof the funnel member 70, formed by the funnel insert 30 and the funnelportion 40 of the filler tube 32, provides an arrangement that induces aswirling motion to the fuel as the fuel flows toward the filler tube 32and fills the fuel tank 14 depending on the type of fuel nozzle used.The offset axial relationship of the inlet opening 54 and outlet opening58 causes supplied fuel to impinge a sidewall 28 (coincident with thetransition portion 26 of the filler tube 32) of the funnel member 70,whereby fuel spirals as it flows through the filler tube 32. Theswirling motion of the fuel created by the funnel member 70 causes asuctioning effect or liquid seal that prevents fuel vapors from escapinginto the atmosphere during refueling. The swirling motion of the fuelalso creates a central void that allows any pressure buildup createdduring the fueling to vent, thereby preventing premature shutoff of thefuel nozzle 24.

The funnel member 70 includes a relatively larger diameter section 72forming the inlet opening 54, which is arranged about an axis 74 andspaced-apart axially offset from a relatively smaller diameter tubularsection 76 arranged about an axis 78 forming the outlet opening 58. Asshown, axes 74 and 78 are parallel, but can be positioned divergently.

The larger diameter section 54 and the smaller diameter section 58 areconnected to one another by the transition portion 26, which generallytapers from the larger diameter section 54 to the smaller diametersection 58. The transition portion 26 intersects larger diameter section72 at an elliptically-shaped junction that lies in a plane inclined atangle A, which is 60°–85° from the axes 74, 78. By way of an example,the inlet opening 54 may have a diameter D₁ of approximately 60millimeters and the tubular section might have a diameter D₂ ofapproximately 25 millimeters with a coaxial offset at a distance X ofapproximately 15 millimeters. The relationship of the inlet opening 54and the outlet opening 58 and the configuration of the transitionportion 26 causes the fuel to swirl during fueling.

The fuel filler tube assembly 12 may be made by a number of formingprocesses including eyelet/progressive stamping, eyelet stamping,progressive die stamping, transfer die stamping, and hydroforming. Ifthe fuel tank filler neck is made of plastics, injection molding andcompression molding are suitable methods for manufacturing the fuelfiller tube assembly 12.

The fuel filler tube assembly 12 is manufactured by forming the funnelinsert 30 and expanding the second end 38 of the filler tube 32 tocreate the funnel member 40. The insert end 48 of the funnel insert 32is positioned within the second end 38 of the filler tube 32 in fluidcommunication with the funnel member 40. The joint 34 between the fillertube 32 and funnel insert 30 is formed to mechanically or chemicallysecure to one another. The assembled fuel filler tube assembly 12 isconnected to the fuel tank 14 and the automobile body 22.

The funnel insert 30 is formed by stamping a one-piece seamless tubehaving the larger first diameter portion 42 defining the inlet end 44and the smaller second diameter portion 46 defining the insert end 48including the integrally formed nozzle retainer 60. The stamping methodmay be progressive stamping, wherein sheet stock is formed into acircular blank that is drawn into a cup shape. This drawing method mayinclude several dies in which the funnel insert is progressively formedor deep drawn to shape the first diameter portion 42, the seconddiameter portion 46, and the transition portion 26 therebetween. Theinlet opening 54 of the funnel insert 30 is defined by rolling over anedge of the inlet end 44 to define the sealing surface 50 about theinlet opening 54. The nozzle retainer 60 is defined by piercing thenozzle opening 62 and the vent holes 64 in a bottom surface or insertend 48 of the drawn cup shape.

The filler tube 32 is formed by cutting tube stock to a desired length.The end of the tube stock to receive the funnel insert 30 is flared tocreate the funnel portion 40 by expanding the diameter of the tubethrough an end-forming process. For example, a first punch having afirst diameter is forced into the second end 38 of the filler tube 32.Because the diameter of the first punch is larger than the diameter ofthe second end 38, the insertion of the punch expands the diameter ofthe second end 38. If necessary, this process is repeated with a secondpunch having a diameter larger than the first punch to expand the secondend 38 farther. This process may be repeated as necessary to expand thediameter of the second end 38 of the filler tube 24 to the desireddiameter without severely stressing or weakening the tube. The fillertube 32 is also bent to accommodate the geometry of a particularautomotive vehicle application.

With reference to FIG. 7, the threads 52 may be formed in the funnelinsert 30 by a forming tool 90 including wheels 92, 94, which incombination are of appropriate shape to form the threads 52 in thesidewall of the funnel insert 30. The wheels 92, 94, which are mountedon shafts 96, 98, spin in directions A, B as they press on the sidewall38 to form the threads 36. This spinning allows forming tool 90 to formthe periphery of the funnel insert 30 about the inlet opening 54.

With reference to FIG. 8, another method of forming threads 52 in thefunnel insert 30 is provided. The threads 52 are made by a crimping tool100, which includes crimping halves 102, 104. The sidewall is placedbetween crimping halves 102, 104, which are pressed together indirections A, B to form the threads 52. This process is repeated alongthe sidewall 38 until the threads 52 are completely formed in the funnelinsert 30 about the inlet opening 54.

The funnel insert 30 and filler tube 32 are aligned and joined by thejoint 34, which may be a weld, braze, adhesive, or some other mechanicalor chemical joint. The integrity of the funnel insert 30, filler tube 32and the joint 34 may be leak tested to verify the integrity of thecomponents and their interconnection.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A method comprising: forming a funnel insert with a first diameterportion larger than a second diameter portion; forming a filler tubeincluding a funnel portion having a first diameter and a first axis andan elongated portion having a second diameter smaller than said firstdiameter and a second axis offset from said first axis; attaching saidfunnel portion of said filler tube to said second portion of said funnelinsert; and configuring a transition portion of said funnel portion toinduce a swirl to passing fuel for venting vapors from said fuel tankduring fuel filling.
 2. The method of claim 1, further comprisingforming a sealing surface about an inlet opening to said funnel insert.3. The method of claim 2, wherein said forming a sealing surfaceincludes rolling over an edge defining the inlet opening.
 4. The methodof claim 1, further comprising cutting a length of tube stock to formsaid filler tube.
 5. The method of claim 1, further comprising forming anozzle receptor in said funnel insert.
 6. The method of claim 1, furthercomprising joining opposite ends of a vent tube to said funnel portionand said fuel tank, respectively.
 7. The method of claim 1, furthercomprising joining a vent tube to said funnel portion of said fillertube.
 8. The method of claim 1, further comprising forming threads insaid funnel insert.
 9. A fuel filler tube assembly comprising: a funnelportion of a filler tube including a tubular body defining an inletlarger than an outlet, said inlet of said funnel portion having a firstaxis and receiving a funnel insert including a nozzle opening positionedto cooperate with an internal configuration of said tubular body betweensaid inlet and said outlet to induce a swirl to vent vapors from fuelflowing through said tubular body, said outlet having a second axisoffset from said first axis.
 10. The fuel filler tube assembly of claim9, wherein said outlet of said filler tube is attached to a fuel tank.11. The fuel filler tube assembly of claim 9, further comprising a venttube connected to said filler tube.
 12. The fuel filler tube assembly ofclaim 11, wherein said vent tube also connects said filler tube and saidfuel tank.
 13. The fuel filler tube assembly of claim 9, wherein saidinternal configuration of said tubular body includes a tapered sectionof said tubular body.
 14. The fuel filler tube assembly of claim 13,wherein said tapered section includes an elliptically shaped junctionbetween a first portion of said tubular body including said inlet and asecond portion of said tubular body including said outlet.
 15. The fuelfiller tube assembly of claim 14, wherein said elliptically-shapedjunction lies on a plane inclined at an angle to an axis of at least oneof said inlet and said outlet.
 16. The fuel filler tube assembly ofclaim 14, wherein said inlet has a diameter D₁, said outlet has adiameter D₂, and D₁ is at least one and a half times D₂.
 17. The fuelfiller tube assembly of claim 9, wherein said filler tube is a seamlesstube.
 18. The fuel filler tube assembly of claim 9, wherein said funnelinsert is a seamless tube.
 19. The fuel filler tube assembly of claim 9,wherein said funnel insert includes integrally formed threads.
 20. Thefuel filler tube assembly of claim 9, further comprising a fuel capselectively engaging said funnel insert.
 21. The fuel filler tubeassembly of claim 9, wherein said funnel insert includes a sealingsurface operable to selectively engage said fuel cap.
 22. The fuelfiller tube assembly of claim 21, wherein said funnel insert includes alarger diameter portion having an inlet opening creating said sealingsurface.
 23. A method comprising: drawing a funnel insert with a firstdiameter portion larger than a second diameter portion; forming a funnelportion at an end of a filler tube, an opposite end of said filler tubebeing operable to be directly attached to a fuel tank; forming arelatively large inlet at one end of said funnel portion, said inlethaving a first axis; forming a relatively small outlet at said oppositeend of said funnel portion, said outlet having a second axis offset fromsaid first axis; joining said second diameter portion of said funnelinsert and said funnel portion of said filler; and configuring atransition of a tubular body between said inlet and outlet to induce aswirl to and vent vapors from fuel flowing through said funnel portion.24. The method of claim 23, further comprising attaching said oppositeend of said filler tube to a fuel tank.
 25. The method of claim 23,further comprising forming threads in said first diameter portion ofsaid funnel insert.
 26. The method of claim 23, further comprisingforming a sealing surface about said first diameter portion of saidfunnel insert.
 27. The method of claim 26, wherein said forming asealing surface includes rolling over an edge defining an inlet opening.28. The method of claim 23, further comprising forming a nozzle receptorin said second diameter portion of said funnel insert.
 29. The method ofclaim 23, further comprising cutting a length of tubing stock to formsaid filler tube.
 30. The method of claim 23, further comprising joiningan end of said filler tube opposite said funnel insert to said fueltank.
 31. The method of claim 30, further comprising joining oppositeends of a vent tube to said funnel portion and said fuel tank,respectively.
 32. The method of claim 23, further comprising joining avent tube to said funnel portion of said filler tube.
 33. A fuel fillertube assembly comprising: a filler tube including a tubular bodydefining an inlet larger than an outlet; and a funnel insert including afirst cylindrical section, a second cylindrical section, a thirdcylindrical section disposed between said first cylindrical section andsaid second cylindrical section, and a tapered surface extending betweensaid first cylindrical section and said third cylindrical section, saidfirst cylindrical section received in said inlet of said filler tubewith said tapered surface engaging a surface of said inlet when saidfirst cylindrical section is disposed within said inlet of said fillertube.
 34. The fuel filler tube assembly of claim 33, wherein said funnelinsert is a seamless tube.
 35. The fuel filler tube assembly of claim33, wherein said funnel insert includes integrally formed threads. 36.The fuel filler tube assembly of claim 33, further comprising a fuel capselectively engaging said funnel insert.
 37. The fuel filler tubeassembly of claim 33, wherein said funnel insert includes a sealingsurface formed about said second cylindrical section.
 38. The fuelfiller tube assembly of claim 37, wherein said second cylindricalsection includes an inlet opening and a portion of said funnel insertdefining said inlet opening creates a sealing surface.
 39. A fuel fillertube assembly comprising: a filler tube including a tubular bodydefining an inlet larger than an outlet; and a funnel insert including afirst section, a second section, and a tapered surface extending betweensaid first section and said second section, said first section receivedby said inlet of said filler tube and including a nozzle retainer;wherein said tapered surface engages a surface of said inlet when saidfirst section is disposed within said inlet of said filler tube.
 40. Thefuel filler tube assembly of claim 39, wherein said funnel insert is aseamless tube.
 41. The fuel filler tube assembly of claim 39, whereinsaid funnel insert includes integrally formed threads.
 42. The fuelfiller tube assembly of claim 39, further comprising a fuel capselectively engaging said funnel insert.
 43. The fuel filler tubeassembly of claim 39, wherein said funnel insert includes a thirdsection formed adjacent said second section.
 44. The fuel filler tubeassembly of claim 43, wherein a sealing surface is formed about saidthird section.
 45. The fuel filler tube assembly of claim 44, whereinsaid third section includes an inlet opening and a portion of saidfunnel insert defining said inlet opening creates a sealing surface. 46.A method comprising: drawing a funnel insert with a first diameterportion larger than a second diameter portion; forming a funnel portionat an end of a filler tube, an opposite end of said filler tube beingoperable to be directly attached to a fuel tank; forming a relativelylarge inlet at one end of said funnel portion, said inlet having a firstaxis; forming a relatively small outlet at said opposite end of saidfunnel portion, said outlet having a second axis offset from said firstaxis; joining said second diameter portion of said funnel insert andsaid funnel portion of said filler tube; and forming a nozzle receptorin said second diameter portion of said funnel insert.
 47. The method ofclaim 46, further comprising attaching said opposite end of said fillertube to a fuel tank.
 48. The method of claim 46, further comprisingconfiguring a transition of said tubular body between said inlet andoutlet to induce a swirl to and vent vapors from fuel flowing throughsaid funnel portion.
 49. The method of claim 46, further comprisingforming threads in said first diameter portion of said funnel insert.50. The method of claim 46, further comprising forming a sealing surfaceabout said first diameter portion of said funnel insert.
 51. The methodof claim 50, wherein said forming a mug surface includes rolling over anedge defining an inlet opening.
 52. The method of claim 46, furthercomprising cutting a length of tubing stock to form said filler tube.53. The method of claim 46, further comprising joining an end of saidfiller tube opposite said funnel inert to said fuel tank.
 54. The methodof claim 53, further comprising joining opposite ends of a vent tube tosaid funnel portion and said fuel tank, respectively.
 55. The method ofclaim 46, further comprising joining a vent tube to said funnel portionof said filler tube.